What are the factors that affect the particle size of the high pressure roller mill?
High-pressure roller mills are widely used in major mines and related material crushing industries. They have the characteristics of large production capacity, fine particle size, low unit crushing energy consumption and steel consumption. After years of research, it has been found that the particle size of the high-pressure roller mill is not only related to the properties of the original ore, but also to factors such as operation.
Factors affecting the particle size of the high-pressure roller mill
1. Roller surface pressure
Through experiments, it was found that increasing the roller surface pressure of the high-pressure roller mill will make the particle size of the middle and side materials finer, the particle size distribution of the middle material more concentrated, and the particle size distribution of the side materials more uniform. The crushing effect of the high-pressure roller mill on the material mainly depends on the pressure on the material near the small gap between the two rollers. The specific pressure (the ratio of the total pressure provided by the hydraulic system to the diameter and width of the roller) is usually used as an operating parameter to measure the working pressure.
As the roller surface pressure increases, the uniformity coefficient of the intermediate material increases, the particle size distribution becomes more concentrated, the crushing ratio increases, the discharge particle size becomes finer, and the fine-grained part of the intermediate material after crushing accounts for the majority; as the roller surface pressure increases, the uniformity coefficient of the side material decreases, the particle size distribution becomes wider, the crushing ratio increases, the discharge particle size becomes finer, and the high-pressure roller mill side material is closer to the conventional crushing product.
The fine-grained part of the intermediate material after crushing accounts for the majority, because in the crushing process, the “size effect” of mineral particles (the mechanical strength of ore particles increases significantly with the decrease of ore size) makes fine-grained materials more difficult to crush or no longer crushed than coarse-grained materials under a certain roller surface pressure, so that the fine-grained part of the product accounts for the majority.
The side material of the high-pressure roller mill is closer to the conventional crushing product, which is caused by the “edge effect” of the roller during the crushing process. The lower roller surface pressure of the baffles at both ends of the roller and the edge of the roller makes it easy for the material to slide relative to the edge of the roller, weakening the crushing effect of the material layer, so that the crushing method of the roller edge on the material is closer to the conventional crushing method.
2. Roller surface speed
Under the same roller surface pressure, when the roller surface speed increases to a certain amount, the uniformity coefficient of the intermediate material increases, the particle size distribution is more concentrated, the crushing ratio increases, and the product particle size becomes finer, but the influence on the uniformity coefficient of the side material and the change in the crushing ratio are not obvious; but when the roller surface speed continues to increase, the change in the crushing ratio of the intermediate material is no longer obvious.
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